Comparison and validation studies related to the modeling ionospheric convection and the European incoherent scatter observations in the polar cap

Abstract

[1] We use the ionospheric velocity measurements obtained by the European incoherent scatter (EISCAT) Svalbard radar (ESR) for comparison with the electric field distribution predicted by the new ionospheric convection model based on realistic maps of field-aligned currents. The comparative analysis of model output and observations is based on the data contained both the north–south and east–west components of the ionospheric electric field. Such a comparison provides an independent check of the model. It is shown that the model represents accurately the large-scale features of statistical electric field inferred from the ion velocity measured by the ESR. From observations and modeling we quantitatively determine the dependence of the ionospheric electric field strength on the IMF conditions and how this varies with magnetic local time. For specification of the relationship we derive average convection patterns for sorting by the magnitude and direction of the IMF. The dependence is clearly seen by contrasting the results for two magnitudes of the IMF strength (BT = 1 and 5 nT), for two opposite directions of the IMF Bz component, and for By+, By−. The magnitude of the IMF has the main impact on the average flows under southward IMF conditions. The sign of IMF By is the most important factor influenced the convection system under the IMF northward. For By− the northward component is negative during a major part of the day indicating counterclockwise plasma flow around the pole. For By+, the situation is opposite, the electric field is directed poleward and the plasma rotate clockwise. These are confirmed nicely by the ESR observations.